1. Field of the Invention
The present invention relates to sealing techniques for fluid passages and, more particularly, to sealing techniques for use in apparatuses that fabricate semiconductor integrated circuits (ICs).
2. Description of the Related Art
During the manufacture of a semiconductor-based product, for example, a flat panel display or an integrated circuit, multiple deposition and/or etching steps may be employed. By way of example, one method of etching is plasma etching. In plasma etching, a plasma is formed from the ionization and dissociation of process gases. The positively charged ions are accelerated towards the substrate where they drive the etching reactions. Typically, during the etching process, the plasma environment inside the plasma processing apparatus, is held at very low pressures (e.g., 5-30 mTorr). If the pressure is not maintained at an appropriate level during the processing of the substrate, then undesirable and/or unpredictable etch results may be produced. For example, if the pressure is too low, then the electrons inside the plasma have long mean free paths and may not collide with enough molecules before the electrons are lost to the chamber wall thereby adversely impacting the plasma that drives the etching reactions.
For this reason, a manometer is used to measure the pressure. Typically, a manometer is coupled through a series of connections to a process chamber in a plasma processing apparatus. The readings of the manometer give computer the ability to make adjustments to ensure that the pressure inside the process chamber is correct for a particular processing step. Unfortunately, the series of connections that couple the manometer to the process chamber may have leaks. Leaks in the measuring pathway create false measurements and inaccurate readings at the manometer that lead to adverse processing results. The minimum drift in pressure should be less than 5 mTorr. However, in some instances, the loss due to leaks may be in the range of 20 mTorr of flow.
To facilitate discussion of this leakage problem, FIG. 1A and 1B illustrate a typical layer assembly 100 that has a leak. FIG. 1A shows a front, side and top view of the layer assembly 100, and FIG. 1B shows a perspective view of the layer assembly 100. Layer assembly 100 includes a first layer 102 having a first cylindrical passage 104 and a second layer 106 having a second cylindrical passage 108. Typically, first layer 102 includes a surface 110 that is in contact with a surface 112 of second layer 106. Each layer represents a different piece of equipment found in a typical plasma processing apparatus (e.g., quartz ring, focus ring, etc.). Additionally, the passages are used to couple the process chamber (not shown) with the manometer (not shown). In order to allow the transfer of fluid for measuring, first cylindrical passage 104 and second cylindrical passage 108 must substantially align along an axis 114. However, even if they are aligned properly, the adjacent surfaces of the layers will form a gap 116 at their interface because of unequal surfaces caused by a plurality of finishing techniques (e.g., different finishing process, different material, scratches, etc.). Gap 116 allows the passage of fluid and therefore creates unwanted fluid leaks 118.
For the most part, conventional o-rings may be used to reduce the leaks created by gap 116. The o-ring seals the interface between the first cylindrical passage 104 and the second cylindrical passage 108 thereby reducing the leaking fluid. To elaborate further, FIG. 2 includes a layer assembly 200. The layer assembly 200 is generally constructed the same as the layer assembly 100 but further includes an o-ring 202. O-ring 202 is disposed in between first layer 102 and second layer 106 and surrounds the perimeter of first cylindrical passage 104 and second cylindrical passage 108. The o-ring 202 serves to prevent a fluid from leaking out of the interface of first cylindrical passage 104 and second cylindrical passage 108.
It would be preferable to design interfaces that are the same shape, especially circular shapes where conventional o-rings may be used. However, recent technology has required increasingly complicated fluid passages that are constrained by limited space. For example, if one fluid passage is square-shaped and the other is circle-shaped, a standard o-ring may not be able to seal the interconnection of the different shaped fluid passages. Further, when the width of the layer around the fluid passage is narrow, there may not be enough room to place an o-ring.
By way of example, FIGS. 3A-3C illustrate a layer assembly 300 with fluid passages that have different shapes. FIG. 3A depicts an exemplary situation where two layers with complicated fluid passages and limited space are coupled together. As shown, the layer width is constrained by the inside diameter and the outside diameter of the interfacing layers. In addition, FIG. 3B shows a front view, side view and top view of a section in layer assembly 300 that includes the fluid passages of the two layers shown in FIG. 3A.
Layer assembly 300 includes a first stack layer 302 having first a fluid passage 304 and a second layer 306 having a second fluid passage 308. First fluid passage 304 is a passage having a circular shape (cylindrical passage). Second fluid passage 308 is a passage having an irregular shape (e.g., oval, rectangle, square, triangle, polygon, etc.). As shown in FIG. 3B, first fluid passage 304 and second fluid passage 308 cannot properly align about an axis 310 because of their different geometries. As a result, the interface between first fluid passage 304 and second fluid passage 308 will tend to leak. If o-ring 312 is used between the interfacing layers, then part of o-ring 312 will be disposed outside the limited width of the two interfacing layers. Therefore, the gaps at the interface will not be sealed and fluid leaks will ensue. As noted above, in the case of plasma processing apparatuses, such leaks lead to unwanted processing results due to inaccurate manometer pressure readings.
In view of the foregoing, there is a need for improved techniques for sealing two adjacent fluid passages that are constrained by different shapes and limited space.
The invention relates, in one embodiment, to a fluid connector for sealing an interface between first and second fluid passages in a plasma processing apparatus. The fluid connector includes a first end member having a first geometry. The first geometry is arranged to substantially seal a first mating region of the first fluid passage. The fluid connector further includes a second end member having a second geometry. The second geometry is arranged to substantially seal a second mating region of the second fluid passage. The second geometry is configured differently than the first geometry. The fluid connector additionally includes an opening that extends through the first end member and the second end member through which a fluid may pass for use by the semiconductor processing apparatus so as to fluidly couple the first fluid passage to the second fluid passage.
The invention relates, in another embodiment, to a system for sealing an interface between at least two fluid passages. The system includes a first surface having a first fluid passage with a first geometry. The system further includes a second surface having a second fluid passage with a second geometry. The second geometry is different from the first geometry of the first fluid passage. The system additionally includes a connector for sealing the first fluid passage with the second fluid passage. The connector has a proximal section and a distal section. The proximal section is configured to at least partially extend into the first fluid passage and has a shape that coincides with the first geometry such that the connector is substantially sealed with respect to the first fluid passage. The distal section is configured to at least partially extend into the second fluid passage and has a shape that coincides with the second geometry such that the connector is substantially sealed with respect to the second fluid passage. Also, the connector includes an opening that provides a sealed fluid passage between the first fluid passage and the second fluid passage.
The invention relates, in yet another embodiment, to a plasma processing apparatus. The plasma processing apparatus includes a chamber associated with a first fluid passage. The plasma processing apparatus further includes a manometer associated with a second fluid passage. The plasma processing apparatus additionally includes an interconnection sealer for sealing an interface between the first fluid passage and the second fluid passage. The interconnection sealer includes a first end member having a first geometry. The first geometry is arranged to substantially seal a first mating region of the first fluid passage. The interconnection sealer further includes a second end member having a second geometry. The second geometry is arranged to substantially seal a second mating region of the second fluid passage. The second geometry is configured differently than the first geometry. The interconnection sealer additionally includes an opening that extends through the first end member and the second end member through which a fluid may pass so as to fluidly couple the first fluid passage to the second fluid passage.
Also, the invention relates, in one embodiment, to a method of sealing fluid passages of different shapes. The method includes identifying a first surface including a first fluid passage having a first geometry. The method further includes identifying a second surface including a second fluid passage having a second geometry. The second geometry is different from the first geometry. The method additionally includes fitting an interconnection sealer for use with the first fluid passage and second fluid passage. The interconnection sealer includes a proximal section and a distal section. The proximal section is configured to at least partially extend into the first fluid passage and has a shape that coincides with the first geometry such that the interconnection sealer is substantially sealed with respect to the first fluid passage. The distal section is configured to at least partially extend into the second fluid passage and has a shape that coincides with the second geometry such that the interconnection sealer is substantially sealed with respect to the second fluid passage. The interconnection sealer further includes an opening that provides a fluid passage. The method further includes inserting the interconnection sealer into the first fluid passage and the second fluid passage and substantially sealing the first fluid passage and the second fluid passage with the interconnection sealer.